Audience affects decision-making in a marmoset communication network

Abstract

An audience can have a profound effect on the dynamics of communicative interactions. As a result, non-human primates often adjust their social decision-making strategies depending on the audience composition at a given time. Here we sought to test how the unique vocal behaviour of multiple audience members affected decisions to communicate. To address this issue, we developed a novel experimental paradigm in which common marmosets directly interacted with multiple 'virtual monkeys' (VMs), each of whom represented an individual marmoset with distinct vocal behaviour. This active social signalling paradigm provided subjects an opportunity to interact with and learn about the behaviour of each VM in the network and apply this knowledge in subsequent communicative decisions. We found that subjects' propensity to interact with particular VMs was determined by the behaviour of each VM in the audience and suggests that marmoset social decision-making strategies are highly adaptive to nuances of the immediate communication network. BackgroundThe composition of an audience is known to affect the patterns of communication in a diversity of animal species [1][2][3][4][5][6]. Given that the individuals within a particular social scene can change over time, non-human primates must monitor these changes and adapt their social decision-making strategies accordingly [7,8]. Despite the fact that networks of multiple individuals, and not dyadic interactions, are more characteristic of primates and other animals [9], relatively little is known about how individuals change their decisions to communicate based on the unique vocal behaviours of each conspecific in a particular audience. Here we sought to test this issue by implementing a novel active social signalling paradigm designed to simulate a natural primate communication network. In these experiments, a common marmoset (Callithrix jacchus) directly engaged in vocal interactions with multiple 'virtual monkeys' (VMs). Each VM was a speaker that broadcast calls from an individual marmoset from our colony, thus encapsulating the vocal identity of that individual. We then used novel interactive playback software to assign specific behavioural attributes to each individual VM and test whether marmoset decisions were determined solely by the specific behavioural characteristics of a particular VM (independent of the other VM) or whether decisions were made by comparing the behaviour of both VMs in the scene.Marmosets frequently engage in natural vocal exchanges known as antiphonal calling [10]. This behaviour involves the reciprocal exchange of the species-typical phee call between visually occluded individuals, a vocalization encoded with a rich corpus of information about the caller, such as individual identity, sex and group dialect [11]. Similar to contact calls produced by other primates, the phee call functions to alert conspecifics to a signaller's presence when visually occluded. Antiphonal interactions are governed by

Marmoset vocal communication: Behavior and neurobiology

“…In one experiment, the caller identity was unexpectedly changed during the conversation and resulted in significantly decreased responses from marmosets, suggesting that the identification of the individuals in the conversation is particularly salient (Miller and Thomas, ). More recently, we implemented a paradigm in which subjects engage with multiple VMs in order to test social decision‐making within the context of a communication network (Toarmino et al, ). Each VM's vocal behavior was characterized by differences in response latency (Short|Long) and response probability (High|Low) in order to test the extent to which decisions to communicate were based on these behavioral characteristics and/or the behavior of the other VMs in the experiment.…”

Food Calls in Common Marmosets, Callithrix jacchus, and Evidence That One Is Functionally Referential

“…This can be further investigated by determining whether the calls are produced only in the presence of group members (i.e., the ‘audience effect’) [ 6 ]. The audience effect indicates that individuals are not simply vocalising because of a change in their level of arousal, but rather that they are able to control their vocal behaviour depending on the presence or absence of other individuals [ 7 ], and this is particularly seen in the antiphonal calling of common marmosets [ 8 , 9 ]. In fact, the presence of others can increase or decrease call production.…”

Vocal Transmission of Breeding Status May Facilitate Dispersal in a Cooperative Breeding Primate

“…That vocal parameters are not necessarily correlated with age demonstrates that something besides growth or senescence is driving these changes, but they may be hormonal rather than consciously produced. Research on food calls (Caine et al, 1995;Roush & Snowdon, 2000), antiphonal calling (Toarmino et al, 2017) and cooperation (Cronin et al, 2005) has shown that callitrichids do alter their vocalizations based on their perception of others' knowledge and intent. Research targeting the development of vocalizations of secondary breeders would clarify the bases of these changes, and the use of these vocalizations as sexual signals for both males and females.…”